The virulent H5N1 avian flu virus spread across much of Asia from late 2003, causing the death or culling of more than 100 million fowl.

这种致命的H5N1禽流感病毒于2003年底席卷了亚洲大部分地区，导致超过1亿的家禽死亡或被扑杀。

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Health officials believe people are contracting the virus through direct contact with infected fowl and say there has been no evidence so far that the virus is spreading easily between people.

NPR: China Kills Market Birds As Flu Found In Pigeons

Authorities have halted live poultry trade in cities where cases have been reported, and slaughtered fowl in markets where the virus has been detected.

NPR: WHO Talks With China On Sending Bird Flu Team

The virus has been detected in live poultry in several food markets where human cases have been found, leading officials to think people are most likely contracting the virus through direct contact with infected fowl.

NPR: WHO Talks With China On Sending Bird Flu Team